The invention relates to a thread guiding device on a power loom having a fixed weft thread supply bobbin and a thread tensioner supplied therefrom, which comprises a thread guide, which can rotate around an axis of rotation, with an inlet channel for the weft thread passing through said thread guide in the axial direction, with a thread guiding component for the weft thread fixed between the supply bobbin and the thread tensioner and a monitoring device responding to the path of the thread between the thread guiding component and the thread tensioner.
In an appliance of this type known from German Patent Specification 29 08 743 for monitoring the weft thread supplied to the thread storage there is provided an electronic catch thread device having a thread sensor, which is excited by the moving weft thread and which is connected in series via an electronic scanning device and a logical circuit with a stop device. The power loom is switched off by means of the stop device if the weft thread breaks. Such electronic appliances require a relatively expensive control system and their function can be impaired by contamination, depending on the weft thread material being used.
To monitor the weft thread supplied to the thread storage there are also known piezoceramic components, which however require additional deflections in the weft thread so as to achieve a certain thread tension necessary for detecting the path of the thread and, as they react to the "noise" of the moving thread, their function can be impaired by ambient noise, e.g. the hissing of outgoing pressurized air in the case of pneumatic power looms.